code: def _get_plot_backend(backend: str | None = None):
      """
      Return the plotting backend to use (e.g. `pandas.plotting._matplotlib`).
  
      The plotting system of pandas uses matplotlib by default, but the idea here
      is that it can also work with other third-party backends. This function
      returns the module which provides a top-level `.plot` method that will
      actually do the plotting. The backend is specified from a string, which
      either comes from the keyword argument `backend`, or, if not specified, from
      the option `pandas.options.plotting.backend`. All the rest of the code in
      this file uses the backend specified there for the plotting.
  
      The backend is imported lazily, as matplotlib is a soft dependency, and
      pandas can be used without it being installed.
  
      Notes
      -----
      Modifies `_backends` with imported backend as a side effect.
      """
      backend_str: str = backend or get_option("plotting.backend")
  
      if backend_str in _backends:
          return _backends[backend_str]
  
      module = _load_backend(backend_str)
      _backends[backend_str] = module
      return module
  
imports: from __future__ import annotations
  import importlib
  from typing import TYPE_CHECKING, Callable, Literal
  from pandas._config import get_option
  from pandas.util._decorators import Appender, Substitution
  from pandas.core.dtypes.common import is_integer, is_list_like
  from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
  from pandas.core.base import PandasObject
label_desc: Use image node_id 7 for calling a global function with example usage: _get_plot_backend(backend) and returns: module, _backends